Our surgical team including senior and resident surgeons went the rounds of our patients in the morning every day. We argued whether air leakage was found or not at the rounds. The chest drain was removed when air leakage stopped in the standardized management group, regardless of the fluid volume or the surgeon’s preference on postoperative day 1 or later. However, from July 2021, we started early removal of chest drain on postoperative day 0 for a patient undergoing thoracoscopic segmentectomy when air leakage was not detected in the sealing test at the end of operation and postoperatively for 2–4 hours, The patients receiving early removal of chest drain on postoperative day 0 were included in the standardized management group. In the non-standardized management group, the tube was usually removed when air leakage stopped or the daily pleural effusion amount fell below 500 mL (on postoperative day 1 or later); however, tube removal was at the surgeon’s discretion. After discharge, postoperative follow-up using chest X-ray in outpatient ward was performed for any patient on around postoperative day 10 and 30.